How can I make it a straight line axis?
That’s an anti-aliasing issue caused by the graphics card.
What operating system are you using? What graphics card. You put ‘2022’ as the answer for both of those in your forum profile. Please put the right answers in there so we can help you.
are you talking about the fact the red axis on the right looks a bit jagged ? anti-aliasis, as Dave mentioned (also, read the rest of his message)
are you talking about the fact that the axis in the bottom left of your screen are in dotted lines ? that’s normal. always has been.
axis appear as plain lines in positive and dotted lines in negative.